Archers such as bow hunters frequently use compound bows to their advantage. Compound bows have significantly more rigid limbs than traditional or recurve bows and employ a mechanical system, typically a set of pulleys and cables, that offers leverage to the archer while drawing the bow and provides greater velocity when launching an arrow. In order to provide these advantages, the pulleys positioned at the outer ends of the limbs of the bow are linked by tensioning cables. The cables wrap around and turn the pulleys as the bowstring is drawn.
The cables between the pulleys of the bow may interfere with the flight of the arrow. When the bowstring is released, the arrow is launched in the direction of the motion of the bowstring. Because the cable portions are forward of the bowstring, the flight path of the arrow is close enough to the cables to otherwise cause the arrow to be deflected by the cables by contact with the fletchings if a cable guard was not positioned to hold the cables away from the path of an arrow.
Some cable guards are partially flexible cantilever bars attached to the riser handle of the bow and extend rearward to the rest positions of the crossing cables of the bow. The cable guard is attached to the cables to hold them to one side of the bow and out of the path of the arrow and the archer's line of sight.
Cable guards are also used to reduce the amount of torque induced on the riser due to the cable loads. However, in this regard they typically have only limited effectiveness. As the cable tensions increase through the draw cycle, an increasing lateral force is applied to the cable guard due to the cable guard holding the cables laterally away from the flight path of the arrow. This causes the cable guard cantilever to laterally bend, so the free end of the guard is slightly drawn toward the riser. Simultaneously, the limbs of the bow bend inward, causing the pulleys and cables to move rearward with respect to the riser. Therefore, although the cable guard attempts to bend toward the riser, the cables also attempt to draw the cable guard toward the archer. These opposing forces limit the range of motion of the cables and guard. At some point, the rearward component of the tension in the cable overpowers the forward component of the bending of the cantilever cable guard, and the guard is prevented from further bending. This limits the lateral travel and function of the flexible member and adds tension to the cables and applies a moment to the bow that can cause unintended riser flex which negatively impacts accuracy of the bow system.
Other guards use a slide mechanism that moves axially along the cable guard. This is intended to allow the cables to translate easily along the longitudinal direction of the cable guard. But the slide introduces inefficiencies as well, such as increasing the number of moving parts of the guard, causing friction between the slide and the guard holding the slide, and causing an increased moment that twists the bow as it is drawn and released. Usually, a slide mechanism also prevents a beneficial longitudinal force, since the slide must move longitudinally along the length of the guard. The increased tension in the cables coupled with increased longitudinal lever arm distance at full draw cause a larger unfavorable moment on the bow system.
Simply holding the cables to one side of the bow keeps them out of the flight path of the arrow, but also undesirably introduces friction and vibration in the operation of the bow that can cause unnecessary noise and wear on the cable. Thus, some cable guards retain the cables against rollers. The rollers allow the cables to slide along the guard with less friction and vibration while the bow is drawn and released while still keeping the cables out of the path of the arrow. However, because the guard bends as the cables increase tension, the cables often put a significant side load on the wheel bearing assemblies and reduce their effectiveness. Therefore improvements are desired in archery cable guards.